1. Field of the Invention
Embodiments of the present invention generally relate to laser scanning systems and more particularly, to checking flipper integrity in electronically-controlled damped off-resonant laser based symbol scanning mechanisms.
2. Description of the Related Art
One commonly used beam scanning technique involves driving a resonant element bearing a mirror into oscillatory motion within a plane, while a laser beam is directed incident the mirror surface. As the resonant element oscillates, so too does the mirror, causing the incident laser beam to be scanned across a scanning field of substantially planar extent, as well as a bar code symbol disposed therewithin. Some scanning mechanisms utilize strips made of MYLAR® (a mark registered with the United States Patent and Trademark Office (“U.S.P.T.O”) by Dupont) or KAPTON® (a mark registered with the U.S.P.T.O. by Dupont) plastic material are used to realize resonant scanning elements.
In general, laser light reflected from the scanned bar code symbol is collected and detected to produce an electrical signal representative of the scanned symbol. Ultimately, the electrical signal is processed in order to decode the scanned symbol and produce symbol character data representative of the decoded symbol.
Because a laser is being used there are certain health concerns. For example, although the laser used is a low intensity level laser and causes no harm when placed against skin, damage can be sustained in an eye if a stationary laser beam is aimed at the eye. Specifically, the eye will attempt to focus on what it sees, and as a result, even a low intensity laser can damage the eye when viewed over a relatively short interval. In an attempt to address this concern agencies such the Bureau of Radiological Health (“BRH”) mandate that there are power limitations (that the laser must be off) within a small diameter (e.g., 7 mm).
As stated above, the resonant element (e.g., a KAPTON® based flipper) is a moving part which transmits and receives information. There are instances when the KAPTON® based flipper may fail (i.e., not transmit an oscillating laser beam) and require that the laser be turned off to prevent eye injury from a stationary beam and so that the scanning device may be examined. However there are instances when the flipper is flipping properly but an erroneous message is received that the flipper is working improperly. When an erroneous message is received the scanner is needlessly turned off.
Therefore, there is a great need in the art for an improved laser scanning mechanism which avoids the shortcomings and drawbacks of prior art laser beam scanning apparatus and methodologies.